Method of investigating the nature of subterranean strata



Dec, 13, 1927. r 1,652,227

T. ZUSCHLAG METHOD OF INVES'TIGATING THE NATURE OF SUBTERRANEAN STRATAFiled Dec. v, 1926 WAVE LEMT H INVENTOR; Theodor Zwcklag BY ATTOR/ZiPatented Dec. 13, 1927.

UNITED STATES PATENT, OFFICE.-

THEODOR ZUSOHIJAG, OF NEW YORK, N. Y., ASSIGNOR TO THE TAUMACCORPORATION,

OF NEW YORK,

N. Y., A CORPORATION OF NEW YORK.

METHOD OF INVESTIGATING THE NATURE OF SUBTERRANEAN STRATA.

Application filed December 7, 1926. Serial No. 153,195.

My 'nvention relates to the art of investigating the nature ofsubterranean strata by electrlcal means and without direct exploration.

The object of my invention is to improve the procedure, particularly incases where one or more drill holes, or other means of gaining access toan underground location are available.

It is a common experience in the art of exploring subterranean strata bydrilling, to miss valuable deposits of ore, oil, etc. by 'a few feet oreven lnches, without finding the slightest trace to indicate theproximity 0 such deposits. My invention makes use of abortive drillholes of this kind in exploring the region around the holes; but anynatural or artificial passage leading from the surface to a pointbeneath ground, or connecting two points beneath the surface, may beemployed.

My invention consists in inserting an antenna wire in a drill hole orthe like, setting up high frequency oscillations in the antenna, varyingthe frequency of the oscillations, and observing and comparing theresistance characteristic of the antenna for each frequency used. Theground surrounding the hole constitutes the dielectric of the antennasystem and the value of thedielectric varies according to theconductivity of the materials of which the ground is composed. Thus, thepresence of a body of ore or other material having a higher or difierentconductivity than the cla sand, rock or other common strata prevai ingin a given region, will be indicated by changes in the resistancecharacteristic of the antenna system.

I am aware of United States patent to Lowy, No. 1,092,065, whichdescribes. a method of exploring strata by setting up an oscillatingantenna underground taining the natural wave-length, capacity anddamping factor ofthe antenna. provement over this patented methodconsists in imposing a range of forced oscillations upon the antenna andcharting and comparing the variations of the resistance f able toestablish and ascercharacteristic corresponding to the changes offrequency. By this means the indications of ore-bodies or the like arerendered more accurate and, hence, more illuminative, as regardslocation, character and extent of the deposits. The additional factor ofcalculation introduced by the employment of a range of differentfrequencies depends upon the fact that the resistance characteristic varies with the frequency and that this variation in turn is modified bydepartures from uniformity in the surrounding strata.

In carrying out the invention it is desir-' a standard of comparison byascertaining the variations of resistance over a given range offrequencies applied to an antenna which is inserted in ground of 35known composition. With the readings thus obtained the results ofsimilar operations in neighboring holesmay be combined and compared.Those skilled in the art will be enabled to ascertain from data of thiskind the existence of valuable deposits and approximately the locationthreof. 1

In the accompanying drawings, Fig. 1 is a diagrammatic illustration ofan antenna system applied to a drill hole in carrying out my invention;and Fig. 2 is a chart showing two curves representing resistancecharacteristics of an antenna.

In Fig. 1, an antenna 1 is inserted in a drill hole as shown and theupper end of the antenna is connected to ground, preferably through acounterpoise 3. In the antenna circuit are a dynamo 2 or other source ofhigh frequency oscillations and a measuring instrument 4 for indicatingthe reslstance of the antenna system. The manner in which thisarrangement is utilized has been sufliciently set forth above.

In Fig. 2, the curves a, b show the values in ohms of the resistancecharacteristic of an antenna through the indicatedra-nge of wavelengthsor frequencies. Curve a was obtained in a very dry and uniform limestoneregion; curve 6 was obtained from the same antenna in a neighboringdrill hole which was near an ore-body. Th difference in the curves ismanifest and, to those practiced in the art, is significant of theproximity of the ore-body.

I claim:

The method of investigating subterranean strata which consists insetting up an antenna in a drill hole or the like, causing highfrequency oscillations in said antenna, varying the frequency of theoscillations, and ascertaining the resistance characteristic of 10 theantenna for each frequency employed, as a basis for deducing thenature'of the strata surrounding the hole.

The foregoing specification signed at New York city, gust, 1925.

THEODOR ZUSCHLAG.

New York, this 21st day of A11- 15

